A good resource is Novelupdates. It has a forum where you can ask for recommendations, forgotten titles, etc. Just make sure you make an account first so you can access all the site's features like the links to the novels.
https://www.novelupdates.com/
Here's a recommendation list for guide verse novels:
https://www.novelupdates.com/viewlist/99490/
And transmigration is a wide net. Is there a specific sort of transmigration novel you'd like to read?
There's always the classic SVSSS when it comes to transmigration. While in guideverse I'd rec Success oriented guide
Can anyone recommend bl transmigration or guideverse novels? I'm new to the bl novel scene, so I'm not picky.